Approach:
The H9 subtype is the most common avian influenza virus (AIV) subtype in commercial poultry in the world today and is endemic in poultry in Asia and the Middle East where it causes substantial economic losses. H9 AIV is often controlled by vaccination, but there is evidence that like other influenza subtypes, that antigenic variation has occurred resulting in decreased vaccine efficacy. A tool to select the most efficacious vaccines strains by improving antigenic matching is needed to aid control efforts. We aim to develop an antigenic map of H9 AIV with numerous H9 AIVs from around the world using multi-dimensional scaling methods. Once this map is established reference reagents can be selected so that additional isolates can be included. As a second part of the work we will establish criteria for the limits of detection so that antigenic map units can be associated with protection which is critical for vaccine strain selection.